1. Field of the Invention
The present invention relates to wireless communication systems.
2. Description of the Related Art
Communication systems and in particular, wireless communication system are designed to meet the varying demands of their subscribers. Service providers, which are entities that own, operate and properly maintain communication systems, are constantly seeking ways to improve the overall performance of a communication system without incurring substantial cost increases in the operation of such communication systems. In particular, as wireless communication systems become more and more popular, service providers have to provide communication systems that allow subscribers to convey (i.e., transmit and/or receive) relatively larger amounts of information per unit time. The amount of information conveyed per unit time is the information rate. The total amount of information that can be conveyed over a system is usually referred to as a system's capacity. The amount of information that is successfully conveyed (i.e., information transmitted and received without errors) over a communication system is usually referred to as system throughput. Subscribers of a communication system with a certain system capacity are limited in the amount of information they can convey at any instant of time. Depending on the conditions of the communication channels through which the subscribers convey information, the subscriber throughput and/or capacity will not remain fixed. Therefore, there may be times when a subscriber desires to convey information at a certain information rate with a certain throughput, but will not be able to do so because of adverse channel conditions. In particular, the communication system may not be able to accommodate a subscriber desiring relatively higher information rates.
To address the problem of a subscriber's inability to convey information at a desired information rate, subscribers use equipment (e.g., cell phones or mobiles) that have multiple antennas instead of only one antenna. The use of additional antennas in a subscriber's equipment gives the subscriber the ability to convey information at relatively higher rates. However, the increased capacity of the subscriber's equipment through the use of additional antennas will still be limited by the system's capacity at any instant of time. For example, a subscriber equipment having multiple antennas may have the capability and desire to convey information at a certain rate, but will be limited to a lesser rate by the system at a particular instant of time. In sum, it is the system's capacity—not the capacity of a subscriber's equipment—which ultimately governs the rate at which a subscriber conveys information.
High Data Rate (HDR) communication systems are Code Division Multiple Access (CDMA) wireless communication systems over which subscribers convey mostly data information. Data information are typically non-voice information (e.g., text or graphics information) represented in digital format. As with other wireless communication systems service providers of HDR systems want to increase system capacity and throughput of such systems without incurring significant increases in the cost of equipment.
What is therefore needed is a method of increasing capacity and throughput of an HDR communication system without a service provider of such a system having to incur significant increase in cost of equipment.